This script is also available at ns/tcl/ex/simple-webcache.tcl.
Examining its output http.log, one will find that the result of
the absense cache consistency algorithm results in a lot of stale hits.
This can be easily remedied by replacing ``new Http/Cache'' line with:
set cache [new Http/Cache/TTL $ns $node(e)]. For more complicated
cache consistency algorithm examples, see
ns/tcl/test/test-suite-webcache.tcl.